The present invention relates generally to medical/dental devices for fixing bone fractures, anchoring of bones, or anchoring of prosthetics to bones. The device generally relates to molly bolts, expandable screws, or devices/screws with expansion or locking mechanisms. More particularly, the present invention concerns an implant assembly which includes a tubular body portion that can be positively secured within a bore in a bone or prosthetic by expander mechanism at both ends of the tubular body portion.
Use of mechanical locking means for securing bone fractures, anchoring of bones, or anchoring of prosthetic to bone are old in the art. Exemplary of such devices is the device described in U.S. Pat. No. 3,708,883 issued to Flander. An improved dental implant is illustrated and described in U.S. Pat. Nos. 5,004,421 and 5,807,199 issued to Lazarof. The Lazarof dental implant makes use of mechanical securement means. In one form, the Lazarof implant is positively secured within the bore in the bone by two separate but cooperating securement mechanisms. The first securement mechanism comprises self-tapping, external threads provided on the tubular body of the device which are threaded into the bone by rotating the device in a first direction. The second cooperating securement mechanism comprises a plurality of bone penetrating anchor blades formed on the skirt portion of the tubular body which are moved into a bone engagement position only after the implant has been secured into the bone. The anchor blades are moved into the bone engagement configuration by rotating a threaded expander member also in a first direction.